CSS3 loading 动画 小球

要点：

• filter: blur()： 给图像设置高斯模糊效果。
• filter: contrast()： 调整图像的对比度。

HTML：

<div class="g-container">
    <div class="g-first"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
    <div class="g-ball"></div>
</div>

SCSS：

$count: 7;

body,
html {
    width: 100%;
    height: 100%;
    display: flex;
    filter: blur(4px) contrast(8);
    background: #000;
    display: flex;
}

.g-container {
    margin: auto;
    position: relative;
    width: 10vmin;
    height: 10vmin;
}

.g-ball,
.g-first{
    position: absolute;
    top:0;
    left: 0;
    right: 0;
    bottom: 0;
    background: #fff;
    border-radius: 50%;
    transform: translate(-700%, 0);
    opacity: 0;
    // animation: move 3s infinite linear;
}

@for $i from 0 through $count { 
    .g-ball:nth-child(#{$i}) {
        animation: move 3.5s infinite #{$i * 0.2 + 0.1}s linear;
    }
}

.g-first {
    animation: scaleMove 3.5s infinite linear;
}

@keyframes move {
    25% {
        opacity: 1;
        transform: translate(-1vw, 0);
    }
    50% {
        opacity: 1;
        transform: translate(1vw, 0);
    }
    75%,
    100% {
        opacity: 0;
        transform: translate(700%, 0);
    }
}


@keyframes scaleMove {
    25% {
        opacity: 1;
        transform: translate(-1vw, 0);
    }
    35% {
        opacity: 1;
        transform: scale(1);
    }
    70% {
        opacity: 1;
        transform: translate(1vw, 0) scale(2);
    }
    90%,
    100% {
        opacity: 0;
        transform: translate(1vw, 0) scale(1);
    }
}